Metric
conversions are making life more difficult for the mechanic. In
addition to doubling the number of tools required, metric-dimensioned
nuts and bolts are used alongside English components in many new
vehicles. The mechanic has to decide which tool to use, slowing down
the job. The tool problem can be solved by trial and error, but some
metric conversions aren’t so simple. Converting temperature, lengths
or volumes requires a calculator and conversion charts, or else a
very nimble mind. Conversion charts are only part of the answer
though, because they don’t help you "think" metric, or
"visualize" what you are converting. The following examples
are intended to help you "see" metric sizes:

LENGTH

Meters
are the standard unit of length in the metric system. The
smaller units are 10ths (decimeter), 100ths
(centimeter), and 1000ths
(millimeter) of a meter. These common examples might help you to
visualize the metric units:

A
meter is slightly longer than a yard (about 40 inches).

An
aspirin tablet is about one centimeter across (.4 inches).

A
millimeter is about the thickness of a dime.

VOLUME

Cubic
meters and centimeters are used to measure volume, just as we
normally think of cubic feet and inches. Liquid volume measurements
include the liter and milliliter, like the English quarts or ounces.

One
teaspoon is about 4 cubic centimeters.

A liter is
about one quart.

A
liter is about 61 cubic inches.

WEIGHT

The
metric weight system is based on the gram, with the most common unit
being the kilogram (1000 grams). Our
comparable units are ounces and pounds:

A
kilogram is about 2.2 pounds.

An
ounce is about 2 8 grams.

TORQUE

Torque
is somewhat complicated. The term describes the amount of
effort exerted to turn something. A chosen unit of weight or force is
applied to a lever of standard length. The resulting leverage is
called torque. In our standard system, we use the weight of one pound
applied to a lever a foot long, resulting in the unit called a
foot­pound. A smaller unit is the inch-pound (the lever is one
inch long).

Metric
units include the meter kilogram (lever one meter long with a
kilogram of weight applied) and the Newton-meter (lever one

meter
long with force of one Newton applied).
Some conversions are:

A
meter kilogram is about 7.2 foot pounds.

A
foot pound is about 1.4 Newton-meters.

A
centimeter kilogram (cmkg) is equal to .9 inch
pounds.

PRESSURE

Pressure
is another complicated measurement. Pressure is described as a force
or weight applied to a given area. Our common unit is pounds per
square inch. Metric units can be expressed in several ways. One is
the kilogram per square centimeter (kg/cm) . Another
unit of pressure is the Pascal (force of one Newton on an area of
one square meter), which equals about 4
ounces on a square yard. Since this is a very
small amount of pressure, we usually see the kiloPascal, or kPa (1000
Pascals). Another common
automotive term for pressure is the bar
(used by German manufacturers) , which
equals 10 Pascals. Thoroughly confused? Try
the examples below: